JPH0443796Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field of industrial application) The present invention relates to a gas suction tool suitable for guiding gas leaking from an underground pipe to a detector.

(Prior art) To detect gas leaking from a buried pipe, a gas suction tool consisting of an annular seal frame formed of an elastic material attached to the back of the base is usually pressed against the ground surface, and the area surrounded by the seal frame is detected. Sampling of underground gas is carried out by applying negative pressure to the ground, but since such sampling is usually carried out along paved roads, the road surface is rough due to the pebbles that make up the paving material. However, there was a problem in that the seal frame did not necessarily come into close contact with the road surface and negative pressure could not be applied sufficiently.

(Purpose) The present invention was developed in view of the above-mentioned problems, and its purpose is to provide an underground gas suction device that can be closely attached to the surface of a paved road with high airtightness. There is a particular thing.

(Example) Therefore, the details of the present invention will be explained below based on the illustrated example.

Figures 1, 2, and 3 each show an embodiment of the present invention, and reference numeral 1 in the figures represents a substantially circular base having an area large enough for a person to stand on. A rigid pipe 2 which also serves as a handle is erected in an airtight manner so that one end thereof communicates with the back surface.

On the other hand, as shown in FIG. 2, a funnel-shaped opening 3 is bored on the back surface of the base 1 so as to communicate with one end of the pipe 2, and a cross-section "V"-shaped first and second seal frames 4 and 5 are fixed. Reference numeral 6 denotes a sealing auxiliary member disposed between the sealing frame 4 and the sealing frame 5, and as shown in FIG. 6a,
6a... are formed of a plate-like elastic material arranged in a staggered manner, and the base 1 has a height such that at least the protrusions 6a, 6a, 6a... are elastically deformed when the base is pressed against the road. is installed airtight.

In this embodiment, one end of the pipe 2 is connected to a pump via a gas detection cell, and the substrate 1 is placed at the location to be sampled. When a person places a load on the surface of the base 1, the seal frames 4 and 5 undergo elastic deformation to match the shape of the road R under the load. On the other hand, the sealing auxiliary member 6 has convex portions 6a, 6 formed on the surface during the process of elastic deformation.
a, 6a, . . . are fitted into the concave portions r, r, r, . It is compressed to fill the valleys of the road, and even with a large contact area, it makes airtight contact with the road surface. When the pump is operated in such a state, negative pressure acts on the opening 3, so that the base 1 is attracted to the road surface by atmospheric pressure. This acts intensively on the area defined by the negative pressure seal frame 5 of the opening 3, and sucks underground gas through the gaps in the road paving material. In this suction process, depending on the condition of the road surface, the seal frame 4,
5 may ride on pebbles on the road surface and create a gap, but the protrusions 6a, 6 of the seal auxiliary member 6
Since a, 6a, . . . are crushed into a flat plate shape, a high flow path resistance is formed due to the long distance to the opening 3, and airtightness is maintained.

[Example] First and second seal frames are formed from an elastic material having a V-shaped cross section with a height of 1.5 cm on a base having a diameter of 30 cm, and are arranged concentrically with an interval of 6 cm. At the same time, a sheet material having a bottom surface uniformly formed with protrusions with a diameter of 5 mm and a height of 5 mm is placed in a state in which the protrusions protrude from the seal frame surface, that is, the thickness to the top is approximately 2 cm. A suction tool disposed between the seal frame and the second seal frame was prepared.

Using this suction tool, we tested an extremely rough asphalt pavement surface with a base material of pebbles with an average particle size of about 5 to 7 mm, and the surface had not yet been flat-finished, and it was found that complete airtightness could be obtained. did it.

On the other hand, for comparison, when we conducted a similar test using a device without the sealing aid, we found that depending on the degree of pressure applied to the base, it was not possible to obtain airtightness, and airtightness was extremely unstable. It was hot. From these results, it has been found that providing a sealing aid is an extremely effective means for ensuring airtightness.

Furthermore, when a similar test was conducted using only either the seal frame 4 or the seal frame 5 placed directly between the opening and the seal auxiliary material 6, almost the same airtightness could be obtained. . This also confirmed that the sealing aid was extremely effective in ensuring airtightness.

In this example, a convex shape with a diameter of 5 mm and a height of 5 mm is used as the sealing auxiliary material, but this may be changed depending on the roughness of the road, which has many uncertain factors. It is desirable to change the size of the convex portion in proportion to the roughness. To this end, it is preferable to prepare a plurality of types of seal auxiliary materials having different convex portion sizes, and to apply, for example, a pressure-sensitive adhesive to the back surface so that they can be replaced depending on the road conditions.

In addition, in this embodiment, a seal frame with a "V"-shaped cross section is used, but the same effect can be obtained by using a seal frame with a rectangular, semicircular, or "W" cross-sectional shape. That is clear.

(Effects) As explained above, according to the present invention, the sealing auxiliary material made of an elastic material with a plurality of protrusions arranged in a staggered manner is provided closer to the inside of the sealing frame. Even the uneven parts can be brought into close contact according to the shape of the road surface, and high airtightness can be ensured.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing one embodiment of the present invention;
The figure is a perspective view showing the back structure of the above device, FIG. 3 is a sectional view of the same device, FIG. 4 is a perspective view and a sectional view showing an example of the sealing aid material, and FIG. FIG. 6 is an explanatory diagram showing the operation of the conventional device. 1...Base, 2...Pipe, 3...Opening,
4, 5... Seal frame, 6... Seal auxiliary material, 6a
...Protrusion.

Claims (1)

[Scope of utility model registration request] A substrate having a first opening connected to a gas suction mechanism on the front surface and a second opening communicating with the first opening and sucking gas from underground on the back surface, and an outer periphery of the second opening. an elastic sealing frame provided on the back surface of the substrate so as to surround the substrate; and at least two convex portions having dimensions corresponding to the roughness of the road in a staggered manner in the circumferential direction on the inside surrounded by the elastic sealing frame.
An underground gas suction device consisting of an elastic plate with strips.